Spin-processing apparatus and spin-processing method

ABSTRACT

The present invention provides a spin-processing apparatus less likely to produce a mist when an object to be processed is rotated. The apparatus is characterized in that it comprises a cup body having a lower cup and an upper cup mounted relative to the lower cup to be up/down movable, a rotation body retaining the object mounted within the cup body, a step motor rotationally driving the rotation body, an exhaust tube connected to a bottom of the lower cup to allow a gas in the cup body to be exhausted, and a scatter-proof cover provided within the upper cup and mounted above the rotation body.

TECHNICAL FIELD

The present invention relates to a spin-processing apparatus andspin-processing method which wash-processes an object to-be-processed,while rotating it, and dry-processes the object.

BACKGROUND ART

In a liquid-crystal manufacturing apparatus and semiconductormanufacturing apparatus, for example, a step is required to wash, with ahigh purity level, an object to be processed, such as a glass substratefor a liquid crystal and semiconductor wafer. In order to wash and drythe above-mentioned material, it has been practiced that the object,while being spun, is washed by jetting a processing solution, such aspure water, and is dried while being spun without jetting the processingsolution.

In order to perform such processing, use has been made of thespin-processing apparatus. The spin-processing apparatus has a cup body.Within the cup body a rotation body is provided which is rotationallydriven by the rotation drive mechanism. The material is retained on theupper surface side of the rotation body. Above the cup body a nozzle isprovided for jetting a processing solution onto the object.

Therefore, it is possible to wash-process the upper whole surface of theobject by jetting the processing solution from the nozzle onto theobject.

For example, in the case where the object is wash-processed with achemical solution, after the wash-processing has been done with thechemical solution, the object is jetted with pure water as theprocessing solution to perform rinse-processing and, while being spunwithout supplying the processing solution, the rinse-processed materialis dry-processed.

There is sometimes the case where, through the spinning of the rotationbody and jetting of-the processing solution onto the object, a mist isproduced and re-deposited onto the wash- and dry-processed object andthe resultant object is contaminated.

It has been practiced that an exhaust tube is connected to the bottom ofthe cup body to allow the mist which is floated within the cup body tobe sucked and exhausted and, by doing so, the mist is prevented frombeing redeposited on the object to be processed.

Incidentally, the mist is scattered at high speeds from the spinningmaterial outwardly toward a diameter direction and collides against theinner wall surface of the cup body and is reflected. The mist reflectedon the inner wall surface of the cup body is sucked into theabove-mentioned exhaust tube and exhausted from within the cup body.

Since, however, the mist reflected on the inner wall surface of the cupbody is indefinite in direction, part of the mist is scattered in thecup body to a site on which a suction produced at the exhaust tube isnot exerted. For this reason, there is sometimes the case where the mistpart is redeposited on the object without being borne on an air currentin the cup body.

The above-mentioned cup body comprises a lower cup and an upper cupmounted on the lower cup to be up/down movable. In the case where theobject is attached to and detached from the rotation body, the upper cupis lowered to expose the rotation body and the attachment/detachment isdone by, for example, a robot.

According to the cup body thus structured, in order for the upper cup tohave an up/down movable structure, a clearance has to be created betweenthe lower cup and the upper cup. There is sometimes the case where whena suction force is created at the exhaust tube so as to discharge a gaswithin the cup body, outer air is sucked from the clearance between thelower cup and the upper cup. Since a dust is contained in the outer airpassed through the clearance between the lower cup and the upper cut,the object to be processed is sometimes contaminated thereby.

It is to be noted that when the upper cup is moved in an up/down motionwithout creating a clearance between the lower cup and the upper cup, adust is produced due to their slide motion and it is unavoidablydeposited onto the object . From this viewpoint it is better to create aclearance.

In the case where a gas within the cup body is sucked and exhausted bythe exhaust tube, if the direction in which an air flow is producedwithin the cup body and direction in which a suction is created by theexhaust tube within the cup body differ, there is sometimes the casewhere the mist within the cup body is less likely to flow smoothly intothe exhaust tube. As a result, the mist is floated within the cup bodyand, sometimes, it is deposited on the object to be processed.

DISCLOSURE OF THE INVENTION

The object of the present invention is to provide a spin-processingapparatus and spin-processing method which prevents the contamination ofa material to-be-processed by a mist produced within the cup body andthe contamination of the object by outer air entering into the cup bodyfrom a clearance between a lower cup and an upper cup.

According to one preferred embodiment of the present invention, there isprovided a spin-processing apparatus for spin-processing an object to beprocessed, characterized by comprising: a cup body having a lower cupand an upper cup so mounted relative to the low cup through apredetermined clearance, a rotation body provided within the cup bodyand retaining the object, drive means for rotationally driving therotation body, an exhaust tube connected to a bottom of the lower cup toallow a gas within the cup to be drawn off and a scatter-proof coverprovided at an inner wall surface of the upper cover to cover acircumference of the object retained by the rotation body.

By doing so, out of a mist scattered from a spinning material andreflected on the inner wall surface of the upper cup, part of the misttrying to be returned back to the upper surface side of the objectcollides against the outer peripheral surface of the scatter-proof coverand stays there. And it is less likely to be scattered on acircumference, so that it is liable to be sucked toward the exhaust tubeside and the deposition of the mist onto the object is prevented.

According to one preferred embodiment of the present invention, there isprovided a spin-processing apparatus for spin-processing an object to beprocessed, characterized by comprising a cup body having a lower cup andupper cut so mounted relative to the lower cup through a predeterminedclearance to be up/down movable, a rotation body provided within the cupbody and retaining the object to be processed, drive means forrotationally driving the rotation body, an exhaust tube connected to thebottom of the lower cup to allow a gas within the cup body to be drawnoff, and an outer air ingress preventing cover for covering theclearance between the upper cup and the lower cup.

By doing so, even if a gas within the cup body is sucked by the exhausttube so as to exhaust a mist within the cup body, outer air isprevented, by the outer air ingress preventing cover, from entering intothe cup body from the clearance between the lower cup and the upper cup.

According to one preferred embodiment of the present invention, there isprovided a spin-processing apparatus for spin-processing an object to beprocessed, characterized by comprising: a cup body having a lower cupand upper cup mounted relative to the lower cup through a predeterminedclearance to be up/down movable, a rotation body provided within the cupbody and retaining the object, drive means for rotatably driving therotation body, an exhaust tube connected to the bottom of the lower cupto allow a gas in the cup body to be drawn off, and a guide membermounted on an inner bottom of the cup body to guide a gas in the cupbody into the exhaust tube.

By doing so, the mist produced within the cup body and outer airentering on the inner wall surface side of the guide member from thelower cup are guided by the guide member and exhausted from the cup bodyinto the exhaust tube in a better state.

According to one preferred embodiment of the present invention, there isprovided a spin-processing method for spin-processing an objectto-be-processed rotated a rotation body provided within a cup body,characterized by comprising the steps of:

lowering an upper cup and supplying the object on the rotation body, thecup body having a lower cup and upper cup provided relative to the lowercup through a predetermined clearance to be up/down movable;

after supplying the object to the rotation body, lifting the upper cupand covering a circumference of the object;

rotating the rotation body, while drawing off a gas within the cup body,and processing the object; and, after processing the object, loweringthe upper cup and picking up the object from the rotation body.

By doing so, when the object is spun and processing is done whileexhausting a gas within the cup, outer air is prevented from enteringinto the cup body and the object is prevented from being contaminated.

BRIEF DESCRIPTION OF THE INVENTION

FIG. 1 is a cross-sectional view showing a schematic structure of awhole apparatus according to one embodiment of the present invention;

FIG. 2 is a perspective view showing a retaining member thereof;

FIG. 3 is a perspective view showing a relation between a rotation shaftand a locking cylinder;

FIG. 4 is a front view showing a releasing mechanism thereof;

FIG. 5 shows a graph showing a result of experiments thereof; and

FIG. 6 is a cross-sectional view showing a portion of a variant of anouter air ingress preventing cover.

BEST MODE OF CARRYING OUT THE INVENTION

One embodiment of the present invention will be explained below withreference to the accompanying drawings.

An spin-dry processing apparatus of the present invention as shown inFIG. 1 has a body base 1. A cylindrical support 2 is provided in thebody base 1 in a manner to extend through the body base 1 in an up/downdirection. A cylindrical rotation shaft 3 is so provided in the support2 as to have its intermediate section rotatably supported by bearings 4.

The lower end portion of the above-mentioned rotation shaft 3 isprojected out of the support 2 such that a driven pulley 5 is providedat the lower end portion of the shaft 3. A step motor 6 is provided inthe neighborhood of the driven pulley 5. A drive pulley 7 is fitted overa rotation shaft 6 a of a step motor 6 and a belt 8 is provided in atensioned way between the drive pulley 7 and the driven pulley 5.Therefore, if the above-mentioned step motor 6 is operated, then therotation shaft 2 is rotationally driven.

A rotation body 9 with a die 10 joined to an upper surface of therotation shaft 3 is mounted as an integral unit relative to an upper endof the rotation shaft 3. Four retaining members 11 are arranged, asupright members, at a 90° interval in a circumferential direction of therotation body 9 such that these are rotatable through a bush 12. Theretaining member 11 has a cylindrical section 13 as shown in FIG. 2.This cylindrical section 13 has its upper end closed and its lower endopened. A support 14 is downwardly provided from a lower end of thecylindrical section 13. The support shaft 14 is rotatably supported atthe above-mentioned bush 12 (shown in FIG. 1).

A support section 15 with a streamlined cross-section is providedintegral with an upper surface of the cylindrical section 13. A supportpin 16 and locking pin 17 higher than the support pin 16 are providedupright on an top surface of the support section 15. The support pin 16is situated substantially in alignment with a center axis of the support14 and the locking pin 17 is so provided as to be displaced apredetermined dimension off an axis of the support axis.

A semiconductor wafer 21 is retained as an object to-be-processed on thefour retaining members 11, as shown in FIG. 1, in the above-mentionedarrangement. that is, the semiconductor wafer 21 has its marginal edgelower surface portion supported on the support pins 16. With thesemiconductor wafer 21 supported on the support pins 16, the retainingmember 11 is rotated as will be set out below. By doing so, the lockingpins 17 provided on the retaining members 11 are eccentrically rotatedand abut against the outer peripheral surface of the semiconductor wafer21, so that the semiconductor wafer 21 is retained without beingdisplaced in a diameter direction.

A through hole 25 is provided, as shown in FIG. 1, between the rotationbody 9 and the die 10. A nozzle body 26 is inserted into the throughhole 25 in a non-contacting state. The nozzle body 26 has a conicalconfiguration and a nozzle bore 27 has its one end opened at the uppersurface of the nozzle body 26.

An upper end of a support shaft 28 is connected to a lower end surfaceof the nozzle body 26 and the upper portion of the support shaft 28 isretained on a bracket 31. The bracket 31 is rotatably supported by aboarding 29 at the rotation shaft 3. That is, the nozzle body 26 isretained at the bracket 31 through the support shaft 28.

A housing 33 is inserted beneath the bracket 31 in the above-mentionedrotation shaft 3. The upper end of the housing 33 is coupled to thebracket 31 and the lower end portion of the housing 33 is supported by abearing 33 a at the rotation shaft 3 such that it is rotatable.

The above-mentioned housing 33 has a first through hole 34 through whichthe support shaft 28 extends and a second through hole 36 through whicha supply tube 35 connected at one end to the nozzle bore 27 extends. Theother end of the supply tube 35 communicates with a supply section ofsupplying a processing solution, such as a chemical solution and rinsesolution, not shown. Therefore, a processing solution can be jetted fromthe nozzle bore 27 to a lower surface of the semiconductor wafer 21.

A nozzle 30 is arranged above the semiconductor wafer 21 retained at therotation body 9. The nozzle 30 communicates with a supply section ofsupplying a processing solution, such as a chemical solution and rinsesolution, not shown.

Thus the processing solution can be jetted on the upper and lowersurfaces of the semiconductor wafer 21 retained at the retaining member11. That is, the semiconductor wafer 21 can has its upper and lowersurfaces wash- and rinse-processed before being dry-processed.

It is to be noted that, since the nozzle body 26 is held by the supportshaft 28 and arranged in a not-contacted state relative to the rotationshaft 3, the rotation body 9 is not rotated even if it is rotated as oneunit relative to the rotation shaft 3.

On the lower surface side of the above-mentioned rotation body 9, alocking cylinder 41 is rotatably provided at the upper outer peripheralsurface portion of the rotation shaft 3. As shown in FIG. 3, a flange 42is provided on an upper end of the locking cylinder 41 and four latchingpins 43 are projected at a 90° interval in a circumferential direction.

As shown in FIG. 2, the latching pin 43 engages an engaging groove 45opened at one end of a lever 44. The other end of the lever 44 ismounted on the lower end of the support shaft 14 of the retaining member11. Therefore, when the locking cylinder 41 is counter-clockwise rotatedas indicated by an arrow in FIGS. 3 and 4 and the lever 44 is rotated bythe latching pins 43 in the same direction, then the retaining member 11can be rotated, in a clockwise direction as indicated by an arrow inFIG. 2, about the support shaft 14 connected to the lever 44.

Since, by doing so, the locking pin 17 is eccentrically rotated, thelocking pins 17 abut against the outer peripheral face of thesemiconductor wafer 21 supported by the support pins 16, so that thesupport state of the semiconductor wafer 21 can be locked. That is, thesupport wafer 21 supported by the support pins 16 is prevented frombeing displaced in the diameter direction. If the locking cylinder 41 isrotated clockwise, it is possible to release the locked state of thesemiconductor wafer 21 by the locking pin 17.

The locking and unlocking of the semiconductor wafer 21 by the lockingpins 17, that is, the rotation of the locking cylinder 41, are done by areleasing mechanism 51. As shown in FIGS. 3 and 4, this releasingmechanism 51 has a first latching piece 52 provided on the outerperipheral surface of the rotation shaft 3 and situated in a cutout 41 ain the locking cylinder 41 and a second latching piece 53 provided inthe outer peripheral surface of the locking cylinder 41.

A spring 54 is stretched between the first latching piece 52 and thesecond latching piece 53. This spring 54 urges the locking cylinder 41toward the direction of the first latching piece 52 through the secondlatching piece 53. That is, the locking cylinder 41 is urged in acounter-clockwise direction as indicated by an arrow in FIG. 3.

Since, by doing so, the locking cylinder 41 is normally urged by anurging force of the spring 54 toward the counterclockwise direction, theretaining member 11 is clockwise rotated through the latching pin 43 andlever 44, so that the locking pin 17 is set in a locked state in whichit abuts against the outer peripheral face of the locking pin 17.

The releasing of the locked state of the semiconductor wafer 21 by thelocking pins 17 is effected by a first cylinder 61 and second cylinder62 in the above-mentioned releasing mechanism 51 situated near theabove-mentioned step motor 6.

That is, as shown in FIG. 4, a first movable body 64 is slidablysupported by a first linear guide 63 in those directions of arrows onthe first cylinder 61 side. The first movable body 64 is coupled to arod 61 a of the first cylinder 61. By doing so, the first movable body64 is adapted to be reciprocably driven along the first linear guide 63by operating the first linear guide 63.

A pair of sandwiching rollers 65 are provided at the forward end of anupper surface of the first movable body 64 such that it is spaced apredetermined distance away from each other. When the first movable body64 is driven in a forward direction, the sandwiching rollers 65 hold thefirst latching piece 52 as indicated by dash dot lines. By doing so, therotation shaft 3 is prevented from being rotated.

On the second cylinder 62 side, a second movable body 68 is mounted by asecond linear guide 67 such that it is slidable in those directions ofarrows. A pressing roller 69 is rotatably mounted on the forward end ofan upper surface of the second movable body 68. Thus, the pressingroller 69 is driven by the second cylinder 62 in a forward/backwarddirection.

When, with the first latching piece 52 held between the pairedsandwiching rollers 65, the second cylinder 62 is operated to cause thesecond movable body 68 to be driven in a forward direction, the pressingroller 69 mounted on the forward end portion of the second movable bodypresses the second latching piece 53 provided on the locking cylinder41.

By doing so, the locking cylinder 41 is rotated against an urging forceof the spring 54 and, through the latching pin 43 and lever 44, theretaining member 11 is rotated in a direction opposite to that at alocking time. Therefore, the locking pin 17 is eccentrically rotated ina counter-clockwise direction, so that the locked state of thesemiconductor wafer 21 is released.

As shown in FIG. 1, a dog 71 is mounted on the outer peripheral surfaceof the lower end portion of the rotation shaft 3 and the dog 71 isdetected by a microphotosensor 72. The rotation angle of the rotationshaft 3 by the above-mentioned step motor 6 is controlled by a detectionsignal of the microphotosensor 72. That is, when the locked state of thesemiconductor wafer 21 is released, the rotation angle of the rotationshaft 3 is so controlled as to allow the first latching piece 52 andsecond latching piece 53 to be set to predetermined positions relativeto the first and second cylinders 61 and 62.

A cup body 80 is provided above the upper surface side of the body base1. The cup body 80 has a bottomed lower cup 75 with the rotation shaft 3extending through a through hole 75 a in the bottom section and aring-like upper cup 76 whose outer peripheral surface defines apredetermined clearance 79 relative to an inner wall surface of thelower cup 75. A rod 78 of an up/down drive cylinder not shown is coupledto the upper cup 76 and, through the operation of this cylinder, theupper cup 76 is up/down driven.

The above-mentioned cup 76 has its up/down motion stroke so set that it,being in a lifted position, covers the outer peripheral surface of thesemiconductor wafer 21 retained by the retaining member 11 and, being alowered position as indicated by a chain line, has its upper end set toa lower position than the upper surface of the semiconductor wafer 21.

Therefore, with the upper cup 76 lowered to the position indicated bythe chain line in FIG. 1, a not-yet-processed semiconductor wafer 21 issupplied to the retaining members 11 mounted on the rotation body 9, bya robot not shown, and a semiconductor wafer 21 processed with aprocessing solution and then dry-processed can be picked up thereby.

Further, to the bottom of the lower cup 75, a plurality of exhaust tubes77 are connected at a predetermined interval, for example, at a 90°interval, in a circumferential direction. The exhaust tubes 77 areconnected to a suction pump 90 through a gas/water separator forseparating a gas and processing solution, not shown, from each other.Therefore, the processing solution, mist, gas, etc., in the cup body 80can be sucked and discharged under a suction force of a suction pump 90connected to the exhaust tube 77.

A concave, circular arc surface 76 a is formed on an inner wall surfaceof the upper cup 76 and, above the circular arc surface 76 a, acylindrical scatter-proof cover 81 is provided which covers an outerperipheral surface portion somewhat higher than the upper surface of thesemiconductor wafer 21 retained by the retaining member 11. Thisscatter-proof cover 81 has its lower end set somewhat higher than, forexample, about a few millimeters to a few tens of millimeters,preferably about 10 mm higher than, the upper surface of thesemiconductor wafer 21.

The scatter-proof cover 81 is made of a synthetic resin of a bettercorrosion resistance, such as a fluorine resin, and formed as having acylindrical configuration. An upper bending section 81 a is formed onthe upper end portion of the scatter-preventing cover 81 and, forexample, bonded or screwed to the cylindrical arc section 76 a of theupper cup 76. Further, at the lower end portion of the scatter-proofcover 81, a lower bending section 81 b is formed which is bent outwardlyof the diameter direction.

When the rotation body 9 is rotationally driven and the semiconductorwafer 21 retained by the retaining members 11 is rotated as one unit, aprocessing solution from the semiconductor wafer 21 is scattered as amist and the mist is reflected on the circular arc surface 76 a of theupper cup 76.

The mist colliding against the circular surface 76 a is mostly reflecteddownwardly because the circular arc surface 76 a is concave, but thereis sometimes the cases that some is moved upwardly and reflected. Themist moved upwardly and reflected at the circular arc surface 76 acollides against the outer peripheral surface of the scatter-proof cover81, so that the mist is prevented from being deposited on thesemiconductor wafer 21 retained at the retaining members 11.

Further, the lower end portion of the scatter-proof cover 81 providesthe lower bending section 81 b bent outwardly toward the diameterdirection. For this reason, some of the mist scattered from thesemiconductor wafer 21 collides against the inner wall surface of thelower bending section 81 b. The mist colliding against the inner wallsurface is moved and reflected downwardly. For this reason, even if thescatter-proof cover 81 is provided, the reflection of the mist on theinner wall surface and return of it back to the semiconductor wafer 21are prevented by the lower bending section 81 b.

That is, since a distance between the lower end of the scatter-proofcover 81 and the upper surface of the semiconductor wafer 21 is set tobe narrower, the mist reflected on the circular arc surface 76 a of theupper cup 76 is prevented from being redeposited on the upper surface ofthe semiconductor wafer 21. On the other hand, however, some of the mistcollides against the lower end portion of the scatter-proof cover 81.However, the lower end portion of the scatter-proof cover 81 is providedat the lower bending section 81 b and the mist colliding there isreflected downwardly, so that it is prevented from being deposited onthe semiconductor wafer 21.

An outer air ingress preventing cover 82 is mounted on the outerperipheral surface of the upper cup 76. The outer air ingress preventingcover 82, like the scatter-proof cover 81, is made of a synthetic resinof a better corrosion resistance, such as a fluorine resin, and formedto a cylindrical configuration. An L-shaped bending section 82 a isformed on the upper end of the outer air ingress preventing cover 82 andthe bending section 82 a is mounted on, and fixed to, a mount section 76b at the upper portion of the outer peripheral surface of the upper cup76.

On the other peripheral wall of the lower cup 75 a receiving groove 83is formed around a full circumference of the cup as an open-topped one.In the lifted state of the upper cup 76, the lower end portion of theouter air ingress preventing cover 82 is situated in the receivinggroove. By doing so, the upper end portion of the lower cup 75, that is,the outer peripheral portion of the overlapped lower and upper cups 75and 76 in the clearance 79, is covered by the lower end portion of theouter air ingress preventing cover 82.

By covering the above-mentioned clearance 79 with the outer air ingresscover 82, the outer air is prevented from entering into the cup body 80via the clearance 79.

With the outer air ingress preventing cover 82 inserted into thereceiving groove 83, a labyrinthine structure is provided at the outerair ingress preventing cover 82 and an area where the receiving groove83 of the circumferential wall of the lower cup 75 is provided. For thisreason, with the outer air ingress preventing cover 82 inserted into thereceiving groove 83, it is possible to, under a better condition,inhibit the outer air from entering via the clearance 79.

With a liquid kept in the receiving groove 83 and the lower end portionof the outer air ingress preventing cover 82 immersed in the liquid, anair-tightness is kept between the outer air ingress preventing cover 82and the lower cup 75, so that an air ingress via the clearance 79 can bepositively prevented.

Since the upper surface of the upper cup 76 is opened, the outer airenters into the cup body 80. However, the spin processing apparatus isnormally installed within a clean room (not shown). In the clean room,pure air not containing any particles flows from a ceiling toward afloor surface. Since, therefore, the pure water flows from the upperopening of the upper cup 76 into the inside of the cup body 80, thesemiconductor wafer 21 is almost not contaminated by the air.

It may be possible that, as shown in FIG. 6, the outer air ingresspreventing cover 82A is formed as a cylindrical bellows structure withthe use of extendible/contractible rubber and synthetic resin in whichcase its lower end is connected to the upper end of the lower cup 75 andits upper end is connected to the mount section 76 b of the upper cup76.

A guide member 85 is provided on the inner bottom of the lower cup 75and formed to a top-opened umbrella-like configuration with the use of asynthetic resin of a better corrosion resistance such as a fluorineresin. That is, the guide member 85 is made smaller at its upper endface than at its lower end face to provide a cylindrical configurationinclined from the upper end toward the lower end outwardly in a diameterdirection.

The guide member 85 has its upper end inner wall surface situated nearthe outer peripheral surface of the rotation body 9 and its lower endsituated at an intermediate portion in the diameter direction of theopening of the exhaust tube 77 connected to the bottom of the lower cup75.

By exerting a suction force of the suction pump 90 on the cup body 80 amist and gas within the cup body 80 are guided on the inclined outerperipheral surface of the guide member 85 and smoothly exhausted intothe exhaust tube 77. Further, since the lower end of the guide member 85is situated at the intermediate portion in the diameter direction of theexhaust tube 77, a suction force of the suction pump 90 acts, via theexhaust tube 77, upon both the outer peripheral surface side and theinner wall surface side. For this reason, a mist entering not only onthe outer peripheral side but also on the inner wall surface side of theguide member 85, as well as a gas entering on the inner wall surfaceside from the through hole 75 a of the lower cup 75, is exhausted fromthe exhaust tube 77 under a better condition.

In the case where the semiconductor wafer 21 is wash-processed and thendry-processed by the spin dry processing apparatus thus structured,first the upper cup 76 is lowered and a semiconductor wafer 21 issupplied to the rotation body 9 (retaining members 11). Then the uppercup 76 is lifted and the marginal edge portion of the semiconductorwafer 21 retained at the rotation body 9 is covered. And the rotationbody 9 is rotated, while sucking an inside of the cup body 80 by thesuction pump 90, and a processing solution is supplied to the upper andlower surfaces of the semiconductor wafer 21. By doing so, theabove-mentioned semiconductor wafer 21 has its upper and lower surfaces,for example, wash-processed by the above-mentioned processing solution.

After being wash-processed, the supplying of the processing solution isstopped and the rotation body 9 is rotated at a high speed to cause theprocessing solution which is deposited onto the semiconductor wafer 21to be scattered. And the semiconductor wafer 21 is dry-processed.

The processing solution is jetted to the rotating semiconductor wafer 21and the semiconductor wafer 21 is dry-processed, so that the processingsolution is scattered about as a mist and the mist collides against thecircular arc surface 76 a of the upper cup 76. Since the circular arcsurface 76 a is concave, the mist scattered on the semiconductor wafer21 and colliding against the circular arc surface 76 a is mostly moveddownwardly and reflected. For this reason, the mist flows along theouter peripheral surface of the guide member 85 under a suction force ofthe suction pump 90 and is exhausted smoothly into the exhaust tube 77.

Part of the mist reflected on the circular arc surface 76 a of the uppercup 76 is reflected upwardly depending upon the angle at which it isincident on the circular arc surface 76 a. However, the mist reflectedupwardly collides against the outer peripheral surface of thescatter-proof cover 81 provided at the upper portion of the upper cup76. For this reason, the mist reflected upwardly on the circular arcsurface 76 a of the upper cup 76 is prevented from being deposited ontothe semiconductor wafer 21.

The lower end of the above-mentioned scatter-proof cover 81 is formed atthe lower bending section 81 b bent outwardly toward the diameterdirection. For this reason, the mist scattering somewhat upwardly fromthe upper surface of the semiconductor wafer 21 and colliding againstthe inner wall surface of the lower bending section 81 b is reflecteddownwardly. And the mist is guided on the outer peripheral surface ofthe guide member 85 and exhausted into the exhaust tube 77, so that itis not deposited to the semiconductor wafer 21.

In this way, the mist scattered from the rotating semiconductor wafer 21is, under a better condition, prevented from being reflected on theinner wall surface of the upper cup 76 and deposited onto thesemiconductor wafer 21 because the inner wall surface of the upper cup76 is made concave and the scatter-proof cover 81 is provided at theupper cup 76.

Since the mist exhausted into the exhaust tube 77 from within the cupbody 80 is smoothly guided by the outer peripheral surface of theinclined circumferential wall of the guide member 85, the mist is liableto be exhausted from within the cup body 80 due also to being done so.

The mist generated at the wash-processing time by the scatter-proofcover 81 and guide member 85 is smoothly and positively exhausted fromwithin the cup body 80 it follows that at the dry-processing time,almost no mist stays within the cup body. Therefore, the semiconductorwafer 21 after being dry-processing following the wash-processing isprevented from being contaminated by the mist.

Since the cup body 80 is such that the semiconductor wafer 21 isattached to, and detached from, the rotation body 9 by lowering theupper cup 76, the above-mentioned clearance 79 is secured between thelower cup 75 and the upper cup 76. However, there is a risk that theouter air containing particles will enter into the inside of the cupbody 80 from the clearance 79, that is, from the overlapped area of thelower cup 75 and upper cup 76.

However, the overlapped area of the respective cups 75, 76 is covered bythe outer air ingress preventing cover 82 and, for this reason, theouter air is prevented from entering from the clearance 79 of theabove-mentioned outerlapped area into the cup body 80, so that there isno possibility that the outer air containing the particles will bedeposited onto the semiconductor wafer 21.

Further, the guide member 85 provided on the inner bottom of the lowercup 75 has its lower end situated at the intermediate way in a diameterdirection of the exhaust tube 77. For this reason, a suction force ofthe suction pump 90 acting inside the cup body 80 via the exhaust tube77 acts not only on the outer peripheral surface side but also on theinner wall surface side of the guide member 85.

Since the suction force acting on the inner wall surface side of theguide member 85 sucks the outer air entering into the cup body 80 fromthe through hole 75 a of the lower cup 75 without being scattered withinthe cup body 80, the particles contained in the outer air entering fromthe above-mentioned through hole 75 a is prevented from being depositedonto the semiconductor wafer 21.

FIG. 5 shows a result of counting by a particle counter of particlesover the upper surface of the semiconductor wafer 21 retained at therotation body 9. The curve A in FIG. 5 represents the case where thereis neither any scatter-proof cover 81 nor any outer air ingresspreventing cover 82. In this case, if the number of revolutions of therotation body 9 rises to 600 rpm, the number of particles starts toincrease and, at 150 rpm, the number of particles per given unit areasharply increased to about 5100.

The curve B represents the case where only scatter-proof cover 81 isprovided. In this case, in comparison with the curve A, an increasingrate of particles was low against an increase in number of the rotationbody 9 and, when the number of rotations was 1500 rpm, the numbers ofparticles per given unit area was about 3500. That is, it may beconsidered that the reflection of the mist on the upper cup 76 anddeposition of it onto the semiconductor wafer 21 can be suppressed byproviding the scatter-proof cover 81.

The curve C represents the case where the scatter-proof cover 81 andouter air ingress preventing cover 82 are provided. In this case, evenwhere the number of revolutions of the rotation body 9 was 1500 rpm,almost no particles were detected over the upper surface of theabove-mentioned semiconductor wafer 21. That is, it is considered that,by providing the scatter-proof cover 81 and outer air ingress preventingcover 82, the contamination of the semiconductor wafer 21 is reducedwith the above-mentioned effect by the scatter-proof cover 81 and outerair ingress preventing effect by the outer air ingress preventing cover82.

INDUSTRIAL APPLICABILITY

The present invention is not restricted to the above-mentionedembodiment and various modifications of the present invention can bemade. For example, although the semiconductor wafer is listed, as anobject to be processed, in the above-mentioned one embodiment, even if arectangular glass substrate for use in a liquid crystal device is usedinstead of the semiconductor substrate, it is possible to prevent itfrom being contaminated when processing is performed on it with theapparatus of the present invention.

What is claimed is:
 1. A spin-processing apparatus for spin-processingan object to be processed, characterized by comprising: a cup bodyhaving a lower cup and a upper cup so mounted relative to the lower cupthrough a predetermined clearance as to be up/down movable; a rotationbody provided within the cup body and retaining the object to beprocessed; drive means for rotationally driving the rotation body; anexhaust tube connected to the bottom of the lower cup to allow a gas inthe cup body to be drawn off; and a scatter-proof cover provided at aninner wall surface of the upper cup to cover a circumference of theobject retained by the rotation body, the scatter-proof cover beingring-like and having a lower end set to be higher in position than anupper surface of the object retained on the rotation body, and the lowerend of the scatter-proof cover being curved outwardly toward a diameterdirection.
 2. A spin-processing apparatus according to claim 1,characterized in that the inner wall surface of the upper cup is aconcave, circular arc surface.
 3. A spin-processing apparatus accordingto claim 1, characterized in that the clearance between the upper cupand the lower cup is covered with an outer air ingress preventing cover.4. A spin-processing apparatus according to claim 1, characterized inthat a guide member is provided at an inner bottom of the cup body toguide the gas in the cup body into the exhaust tube.
 5. Aspin-processing apparatus according to claim 1, characterized in thatthe clearance between the upper cup and the lower cup is covered with anouter air ingress preventing cover and a guide member is provided at aninner bottom of the cup body to guide the gas in the cup body into theexhaust tube.
 6. A spin-processing apparatus for spin-processing anobject to be processed, characterized by comprising; a cup body having alower cup and an upper cup so mounted relative to the lower cup througha predetermined clearance as to be up/down movable; a rotation bodyprovided within the cup body and retaining the object to be processed;drive means for rotationally driving the rotation body; an exhaust tubeconnected to the bottom of the lower cup to allow a gas in the cup bodyto be drawn off; and an outer air ingress preventing cover for coveringthe clearance between the upper cup and the lower cup, the outer airingress preventing cover being formed to a cylindrical configuration andhaving an upper end mounted on an outer peripheral surface of the uppercup, a receiving groove being provided at a circumferential wall of thelower cup and having an open top, and the outer air ingress preventingcover being slidably received in the receiving groove and having a lowerend portion whose length is so set as to be situated in the receivinggroove with the upper cup in a lifted state.
 7. A spin-processingapparatus according to claim 6, characterized in that a guide member isprovided at an inner bottom of the cup body to guide the gas in the cupbody into the exhaust tube.
 8. A spin-processing apparatus according toclaim 7, characterized in that the guide member is formed to acylindrical configuration inclined outwardly toward a diameter directionas a circumferential wall of the guide member goes from an upper end toa lower end and the lower end of the guide member is located at anintermediate portion in the diameter direction of the exhaust tube.
 9. Aspin-processing apparatus for spin-processing an object to be processed,characterized by comprising: a cup body having a lower cup and a lowercup so mounted relative to the lower cup through a predeterminedclearance as to be up/down movable; a rotation body provided within thecup body and retaining the object to be processed; drive means forrotationally driving the rotation body; an exhaust tube connected to thebottom of the lower cup to allow a gas in the cup body to be drawn off;and an outer air ingress preventing cover for covering the clearancebetween the upper cup and the lower cup, the outer air ingresspreventing cover being formed as an extensible/contractible bellows andhaving one end mounted on an outer peripheral surface of the lower cupand the other end mounted on the outer peripheral surface of the uppercup.
 10. A spin-processing apparatus according to claim 9, characterizedin that a guide member is provided at an inner bottom of the cup body toguide the gas in the cup body into the exhaust tube.